Manufacture of tubes



Patented June 8, 1937 UNITED STATES MANUFACTURE OF TUBES Gavin Smellie McLay, London, .England, assignor to Wellman Scaver Rolling Mill Company Limited, London, England, a company of Great Britain No Brawing. Application January 8, 1936, Se-

rial No. 58,225. In 1935 Claims.

This invention relates to the manufacture of steel tubes and tubular articles by the push bench method in which a square or other sectioned billet is first heated and then cut, or out cold, to

5 the required length, is then re-heated or heated and transferred to a circular container where a punch is forced into it from one end to within a short distance of the other end so that the metal displaced by the punch causes the billet to fill the container, and the billet, now usually termed a bottle, is treated in the push bench apparatus in which it is carried through the series of dies or through passes between rolls by which it is drawn out to a tube which is subsequently stripped from the mandrel.

The present invention has for object method by which the cost of producing tubular articles of steel is reduced and in which certain steps are dispensed with.

For the production of a satisfactory tube without flaws and of constant dimensions it has heretofore generally been considered essential that a forged or rolled billet must be employed. .It has, however, been proposed for the manufacture of a gun tube to cast a steel ingot with a number of longitudinal grooves, remove the head or dis card portion, roughly turn the ingot, cup the front face, pierce it to form a closed ended blank which is trued up and then subject it to a drawing process to convert it into the gun tube.

It has now been discovered that separate sections of a casting have different qualities and that the separate sections will produce tubes of different characteristics. It is advisable that an ingot should not vary throughout its length for the production of a tube.

The present invention comprises a method of producing steel tubes consisting in casting steel into lengths of a required section for the subsequent treatment, breaking or cutting the casting lengths into separate parts, piercing each part to form a closed ended bottle, and then passing the part on a mandrel through push bench drawing apparatus to convert it into a tube on said mandrel.

The container may be separate, from the drawing apparatus and the bottle transferred to said apparatus as is described in the specification No. 1,979,579 or the container may be disposed in front of the front end of the mandrel of the apparatus which first pierces the casting and then carries it through the drawing apparatus, as is described in specification No. 2,008,600.

According to a modification of the invention the broken or out part may be wash-heated or soaked Great Britain April 5,

before complete cooling has taken place to bring it to an even temperature and then pierced and treated in the drawing apparatus whereby considerable saving of heat may be effected.

An advantage of the employment of a casting is that it may be larger in section relatively to the container than. when a forgedor rolled billet is employed because the metal is found to flow back along the punch more easily than with a forged or rolled billet. Thus with a casting the shapernay be such as to produce in a particular container, 'abottle which is considerably longer than can be easily obtained with a forged or rolled billet. The result is a saving of work to be performed in the push bench with the possibility of making a longer tube and also a reduced power consumption in the piercing and pushing operations.

There is consequently less wear on the punches and tools.

The casting is preferably hexagonal in section with chamfered corners so that the unevenness at the back end of the finished tube is reduced with consequent reduction in scrap loss. In some circumstances, however, the casting may be round.

In carrying the invention into effect according,

is broken or cut into the required lengths and the sections are chosen for the type of tube to be produced. For example the middle sections are found to be most satisfactory for the better class of the tubes, the metal being of more even texture and more free from flaws. The bottom sections are found to be a little less satisfactory and the top sections least satisfactory. A section is then ,wash-heated or soaked to bring it to. an even temperature and it is then transferred to a container where a punch is forced into it from one end to within a short distance of the other end so thatthe metal displaced by the punch causes the billet to fill the container and also flow back along the punch. The bottle then produced is stripped from the punch and delivered to a push bench apparatus, for example of the kind described in the specification No. 1,979,579, in front of the mandrel thereof, which is advanced to enter the bottle and carry it through the series of dies by which it is drawn out to a tube which is subpassing the part on a mandrel through push:

The back tion for the subsequent treatment, dividing the casting lengths into separate parts, piercing each part to form a closed ended bottle, and then bench drawing apparatus to convert it into a tube on said mandrel.

2. A method according to claim 1 of producing a steel tube wherein the casting is hexagonal in section with chamfered corners. 3. A method of producing steel tubes consisting in casting steel into lengths of a required section for the subsequent treatment, dividing the casting lengthsinto separate parts, heating each part before it has completely cooled from the casting in order to bring it to an even temperature, piercing the part to form a closed ended bottle, and then passing the part on a mandrel through push bench drawing apparatus to convert it into a tube on said mandrel.

4. A method of producing a steel tube, which consists in casting a solid billet, transversely dividing the said billet, in its cast form, into a number of parts, piercing one of the said parts, in the form given it by the division, to produce a bottle and then reducing the bottle to a tube by push-bench drawing on a mandrel.

5. A method of producing a steel tube, which consists in casting a solid billet, transversely dividing the said billet, in its cast form and before ithas completely cooled from the casting, into a number of parts, piercing one of the said parts, in the form given it by the division, to produce a bottle and then reducing the bottle, to a tube by push-bench drawing on a' single mandrel.

' GAVIN SMELLIE McLAY. 

